Teen Mom's Amber Portwood opens up about how she's overhauling her life, body and mind

Amber Portwood has a whole new outlook on being healthy — and she can thank her newfound sobriety for that.

Portwood has appeared significantly slimmer both on Teen Mom and social media since her stint in rehab, and that's no accident. She explains that losing weight has always been a goal, but she knew she had to get her life together first after her stint in jail.

"It's been a journey," she told Cosmopolitan. "What I had to do when I first got out [of jail] was focus on staying sober. But I always wanted to lose weight and get healthy again. That was my next step. When I started to feel comfortable with my sobriety, I was like, 'OK, now it's time to go an extra step.' That takes so much out of you that you really have to be dedicated and have the energy to do it. I've tried to transform my life into something new since I've been out."

Portwood has lost at least 40 pounds and appears noticeably slimmer in recent photos posted to Twitter.

And we get to see how that transformation goes down this season on Teen Mom — not just with her changing shape, but her entire life, including her relationship with her baby daddy Gary Shirley and her attempts to get her daughter Leah back. Let's just say it all adds up to major drama.

"You guys are going to see a part of my life that was a transformation, not only physically but mentally," she told the mag. "You're also going to see me working the hardest that I probably ever have to change the relationship between me and Gary, and getting my daughter back. This is going to be a pretty intense season, I feel. I can't really say season. It's a very intense part of my life."

"There was a time through the custody battle months ago that things were very weird between all of us, and my daughter actually was different. Everybody could see it, not just me. She wasn't wanting to spend time with me, which was very out of character for Leah, because she absolutely loves being with me. I really felt like something was going on. 'Til this day, I'll never know, but it's just how I felt at the time."

Catch Amber Portwood and the rest of the Teen Moms on Teen Mom OG Thursdays on MTV.